Point taken, perneseblue. I don't really like to use more than 50ug/ml even though some protocol requires 100ug/ml. For plate, I think 50ug/ml is more than enough. Different case for broth though.

I do agree with the old plates. By keeping 100ug/ml amp plates, I guess it will take at least a month and a half?

-timjim-

QUOTE (Krisztina @ Jun 22 2007, 07:43 PM)

What is a satellite colony and how do they look like?Thanks.

satellite colonies are small colonies which grow around the "true" colonies containing the resistance gene. they are non-resistant colonies which grow in a circular pattern around the resistant ones. Resistance is mediated through beta-lactamase, which is produced by the resistant colony in the center. therefore satellite colonies where able to grow on place where the ampicillin is degraded (around the resistant colony).

When I used to cloned several years ago what I did to have fast ready plates was to prepared several bottles with the media (about 125mL) autoclaved them and stored with parafilm at 4%, when needed I just melt them in a double boiler, wait until cool down, add the antibiotic and plate them.